Correlating structural properties with electrochemical behavior of non-graphitizable carbons in Na-ion batteries

Tratnik, Blaž (author), Van de Velde, Nigel Willy (author), Jerman, Ivan (author), Kapun, Gregor (author), Tchernychova, Elena (author), Tomšič, Matija (author), Jamnik, Andrej (author), Genorio, Boštjan (author), Vižintin, Alen (author), Dominko, Robert (author)

We report on a detailed structural versus electrochemical property investigation of the corncob-derived non-graphitizable carbons prepared at different carbonization temperatures using a combination of structural characterization methodology unique to this field. Non-graphitizable carbons are currently the most viable option for the negative electrode in sodium-ion batteries. However, many challenges arise from the strong dependence of the precursor’s choice and carbonization parameters on the evolution of the carbon matrix and its resulting electrochemistry. We followed structure development upon the increase in carbonization temperature with thorough structural characterization and electrochemical testing. With the increase of carbonization temperature from 900 to 1600 °C, our prepared materials exhibited a trend toward increasing structural order, an increase in the specific surface area of micropores, the development of ultramicroporosity, and an increase in conductivity. This was clearly demonstrated by a synergy of small- and wide-angle X-ray scattering, scanning transmission electron microscopy, and electron-energy loss spectroscopy techniques. Three-electrode full cell measurements confirmed incomplete desodiation of Na$^+$ ions from the non-graphitizable carbons in the first cycle due to the formation of a solid−electrolyte interface and Na trapping in the pores, followed by a stable second cycle. The study of cycling stability over 100 cycles in a half-cell configuration confirmed the observed high irreversible capacity in the first cycle, which stabilized to a slow decrease afterward, with the Coulombic efficiency reaching 99% after 30 cycles and then stabilizing between 99.3 and 99.5%. Subsequently, a strong correlation between the determined structural properties and the electrochemical behavior was established.

• Language: English
• Keywords: hard carbon, Na-ion battery, structural properties, carbonization process, SAXS, correlations, porosity, electrochemical performance, chemical structure, electrodes, materials, surface chemistry
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: Str. 10667–10679
• Numbering: Vol. 5, iss. 9
• PID: 20.500.12556/RUL-142006
• UDC: 544.5/.6
• ISSN on article: 2574-0962
• DOI: 10.1021/acsaem.2c01390
• COBISS.SI-ID: 124486403
• Publication date in RUL: 14.10.2022

Record is a part of a journal

• Title: ACS applied energy materials
• Shortened title: ACS app. energy mater.
• Publisher: American Chemical Society
• ISSN: 2574-0962
• COBISS.SI-ID: 39550725

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: elektrokemija, testiranje, ogljik, elektroliti